In recent years, recording media can include disk devices with reading heads facing the magnetic disks. Such disk devices include hard disk drives (HDDs). When reading data from magnetic disks in HDDs, desired data can be obtained by reading magnetic information with one or more read heads from target positions on the rotating magnetic disks and then demodulating the magnetic information. When the reading of the magnetic information from the magnetic disks is completed, the demodulation of the magnetic information is not instantaneously completed. In addition, the magnetic information may not be demodulated in some cases (such as when the read data contains an error). In this case, parameters associated with the reading process are changed and reading is retried. Whether it is necessary to retry the reading is determined after the magnetic information is demodulated or after the demodulated data is verified. When retrying of the reading is required, a rotation waiting time is sometimes necessary before target positions in the circumferential direction of the magnetic disks can be accessed again by a read head of the HDD, which can significantly increase the time required to perform the reading retry. It is desirable to shorten a time necessary for a reading retry.